Muscle mass is not affected by dutasteride

According to a trial, treatment with dutasteride (Avodart), a 5-alpha reductase inhibitor, doesn’t influence negatively on muscle mass in healthy males who apply testosterone.
A research related to this issue was performed. While fat-free mass was increased by 0,6-7,1 kg during 20 weeks in men that were given dutasteride and Testosterone Enanthate, fat-free mass was increased by 0,8-8,1 kg in those who applied placebo and testosterone. As for muscle strength, sexual functions and volume of prostate, they didn’t differ in men of these two groups.
5-alpha reductase inhibitors are applied clinically to treat benign prostatic hyperplasia (BPH) and androgenic alopecia. These are diseases that usually trouble middle-aged and elderly males.
DHT represents the main metabolite of testosterone. But the function of this metabolite in human development is not is not understood. It is supposed that DHT has relevant role in development of prostate and phallus.
Middle-aged and elder males with low testosterone levels that take testosterone medications have risks related to decreased muscle size and sexual troubles.
Nonsteroidal selective androgen receptor modulators (SARMs) are also currently studied and developed. It is confirmed that SARMs and 5-alpha reductase inhibitors are safe because DHT is probably not necessary for effects on muscle mass, strength and sexual life. It is also doubted whether DHT has any role for androgen’s effects on hematocrit, hemoglobin, lipids and several other factors.
Shalender Bhasin and his colleagues at the Boston University have conducted a clinical trial in order to define whether 5?-reduction to DHT is needed in order to mediate androgen’s effects on muscle mass. Furthermore, the scientist evaluated role of 5?-reduction on sexual activity, hematocrit and levels of lipid.
The study conducted by Bhasin and his colleagues implicated healthy males who were 18- 50 years old and had normal testosterone levels. They were given Testosterone Enanthate and dutasteride or placebo. Doses of Testosterone Enanthate varied from 50 to 600 mg per week.
Since 5 ?-reductase inhibitors enhance testosterone levels, all men were given also gonadotropin-releasing hormone agonist in order to block natural testosterone.
The results of the study displayed that fat-free mass was enhanced due to administration of testosterone. It didn’t differ significantly in males of these two groups. Muscle power which was also increased due to application of testosterone didn’t differ between the two groups as well. Sexual activity, volume of prostate, sebum production, hemoglobin, acne, hematocrit didn’t differ essentially between those who used placebo and dutasteride.
The specialists state that effectiveness of 5?-reductase inhibitors can be limited in men who have normal or enhanced levels of testosterone. That’s why it is important to check testosterone levels in order to set how bodies will respond to 5 ?-reductase inhibitors.
So, the study has manifested that muscle mass is not affected by 5?-reductase inhibitors.  Males should know that if they have high levels of testosterone or introduce exogenous testosterone in their bodies, 5?-reductase inhibitors will not lead to shrinkage of prostate.